This invention relates to a microwave oven and especially it relates to a combined microwave oven and grill oven which determines from a time-dependent variance in a terminal voltage at a gas sensor, what kind of food is being cooked and then determines automatically when cooking of food is to be completed.
The conventional types of automatic microwave ovens capable of automatically controlling the progress of food cooking with the aid of a sensor or sensors are provided with a predetermined number of keys each for a different kind of food by which different final cooking temperatures are preset.
The present invention improves upon such microwave ovens by providing means which determine what kind of food is being heated and determines and senses its optimum final cooking temperature, based upon a time-dependent variance in a terminal voltage at a gas sensor. This eliminates the need for individual presetting keys for the different kinds of food for automated cooking processes, as fully disclosed in coopending application Ser. No. 393,611 filed June 30, 1982. However, the copending application is not concerned with a combined microwave oven and grill heater oven.